Fast-moving snowstorm threatens holiday travel throughout the West and Midwest

DENVER — Holiday travelers scrambled to adjust their plans Tuesday as a fast-moving snowstorm threatened to bring long delays along with a white Christmas for millions of people throughout the West and Midwest.

The storm system was already snarling traffic in Arizona on Tuesday, with blizzard-like conditions closing roads and causing a pileup involving 20 vehicles. South of Phoenix, a dust storm set off a series of collisions that killed three people.

The blustery weather in Arizona is part of a storm system that promised to bring more than a foot of snow in parts of Colorado and southern Utah by midday today. Blizzard warnings were likely on Christmas Eve in Kansas and other Plains states as the storm moves east. In South Dakota, Gov. Mike Rounds, anticipating blizzard-like conditions, declared a state of emergency Tuesday.

The storm was expected to crawl across the Plains states through Christmas Day, with plenty of snow caused by a tropical jet stream pumping in moisture from the storm's south.

Stan Rose, a National Weather Service meteorologist in Pueblo, Colo., said the storm would give millions of people a white Christmas.

"Pretty much the entire central and southern Rockies are going to get snow, and then it's going east and will drop more snow," Rose said.

A winter storm watch was in effect for most of southeast Colorado, the panhandle of Oklahoma and north Texas from late Tuesday through Thursday. By Tuesday afternoon light snow was falling in Salt Lake City. There were no major airport delays reported there or in Denver, but holiday travelers across the region were warned to check with their airlines before arriving for flights.

In western Nebraska, a Colorado woman was killed Tuesday on Interstate 80 when her sport-utility vehicle apparently hit black ice and slid across a median.